The present invention relates to a power supply, and more particularly to a current-regulated power supply with soft-start protection.
Current-regulated switch mode power supplies operate by monitoring the current through a load and selectively turning a switching On and Off to regulate the current to a desired value. Current-regulated power supplies are employed in a variety of applications, including light-emitting diode products in which the load connected to the current-regulated power supply is comprised of a plurality of light-emitting diodes (LEDs). However, during start-up of a power supply connected to a load having diode-like characteristics, no substantial current flows through the load until a threshold voltage has been reached across the load sufficient to forward bias the diode(s). Without load current feedback, the controller associated with the current-regulated power supply operates in an open-loop mode. As a result, large in-rush current can be generated during start-up. It would therefore be desirable to provide a current-regulated power supply capable of limiting in-rush currents during startup.